Protein malfunction in reproductive disorders

Question 1

Describe the hypothalamus-Pituitary-Gonad axis
(3 main steps)

Answer 1

1. Hypo- produces and releases GnRH
2. Pit gland- anterior lobe releases FSH and LH in response to GnRH
3. FSH and LH then act on the gonads to produce sex hormones and regulate reproductive processes such as the menstrual cycle in females and sperm production in males.

Question 2

How is the H-P-G axis regulated?

Answer 2

The HPG axis operates through a feedback loop. For example, in females, estrogen levels can feedback to the hypothalamus and pituitary to regulate the release of GnRH, FSH, and LH, ensuring proper reproductive function.

Question 3

Why is the H-P-G axis important?

Answer 3

This axis is crucial for the development and maintenance of reproductive functions, including puberty, menstrual cycles, and fertility.

Question 4

GnRH action of gonadotropes: give description on the action in low and high frequecy pulses of GnRH?

Answer 4

Low-Frequency Pulses: These pulses are more effective in stimulating the secretion of FSH, which is important for the development of ovarian follicles in females and sperm production in males.
High-Frequency Pulses: These pulses are more effective in stimulating the secretion of LH, which is crucial for ovulation in females and testosterone production in males

Question 5

What hormone is expressed at ovulation?

Answer 5

LH

Question 6

What is Polycystic Ovarian syndrome (PCOS)

Answer 6

• Enlarged ovaries
• high number of follicles
• endocrine but can still be inherited

Question 7

Why are patients who are affected by PCOS infertile?

Answer 7

Under-developed follicles that cannot ovulate accumulate in the ovaries. this can contribute to infertility

Question 8

What hormonal cause lead to PCOS?

Answer 8

reduced follicle maturation is probably due to low levels of FSH, high levels of androgens and high inhibin.

Question 9

What treatment is used for PCOS?

Answer 9

Clomiphene
it induces the pituitary gland to produce more FSH, which in turn stimulates maturity and release of the eggs.

Question 10

What is Kallman syndrome? What gene is responsible?

Answer 10

Consists of hypogonadotropic hypogonadism
Gene responsible= X-linked for of the syndrome is due to KAL1 which encodes for a protein Ansomnia which plays a key role in the migration of GnRH neurons.

Question 11

What causes the anosmia in males? What do females present?

Answer 11

Hypogonadism secondary to deficiency of hypothalamic GnRH.
Females= trasmitting females have partial or complete anosmia.

Question 12

What hormonal impacts do patients with Kallman syndrome have?

Answer 12

Imparied secretion of FSH and LH

Question 13

What treatment is used for Kallman syndrome

Answer 13

Chorionic gonadotropin can correct cryptorchidism and establish fertility in adult males.

Question 14

What causes autosomal Kallman syndrome (KAL2)?

Answer 14

Mutation in FGFR1

Question 15

What is McCune Albright Syndrome? causes/symptoms etc.

Answer 15

Cause by mosaicism for activating mutations in the GNAS1
Symptom: Precocious puberty- menstatration can occur int he first months of life.

Question 16

What mutation causes delayed puberty?

Answer 16

GPR54 gene mutated.
GPR54 deficient mice had isolated hypogonadotropic hypogonadism in males and delayed vaginall opening in females and absence of follicular maturation in females.

Question 17

What is Kisspeptin? talk about female and male impacts and effect on FSH LH & sex steroids.

Answer 17

Kiss1-null mice fail to undergo sexual maturation
Females do not progress through estrous cycle, do not produce mature Graffian follicles
Males have small testes and spermatogenesis arrested mainly at the early haploid spermatoid stage.
Both sexes have low circulating gonadotropin (FSH & LH) and sex steroids